sql - 如何拆分管道分隔列并将每个值插入新表一次？

Question

我有一个带有大量记录(或多或少)的旧数据库，这些记录有一个标签列(标签以竖线分隔)，看起来像这样:

    Breakfast
    Breakfast|Brunch|Buffet|Burger|Cakes|Crepes|Deli|Dessert|Dim Sum|Fast Food|Fine Wine|Spirits|Kebab|Noodles|Organic|Pizza|Salad|Seafood|Steakhouse|Sushi|Tapas|Vegetarian
    Breakfast|Brunch|Buffet|Burger|Deli|Dessert|Fast Food|Fine Wine|Spirits|Noodles|Pizza|Salad|Seafood|Steakhouse|Vegetarian
    Breakfast|Brunch|Buffet|Cakes|Crepes|Dessert|Fine Wine|Spirits|Salad|Seafood|Steakhouse|Tapas|Teahouse
    Breakfast|Brunch|Burger|Crepes|Salad
    Breakfast|Brunch|Cakes|Dessert|Dim Sum|Noodles|Pizza|Salad|Seafood|Steakhouse|Vegetarian
    Breakfast|Brunch|Cakes|Dessert|Dim Sum|Noodles|Pizza|Salad|Seafood|Vegetarian
    Breakfast|Brunch|Deli|Dessert|Organic|Salad
    Breakfast|Brunch|Dessert|Dim Sum|Hot Pot|Seafood
    Breakfast|Brunch|Dessert|Dim Sum|Seafood
    Breakfast|Brunch|Dessert|Fine Wine|Spirits|Noodles|Pizza|Salad|Seafood
    Breakfast|Brunch|Dessert|Fine Wine|Spirits|Salad|Vegetarian

有没有一种方法可以检索每个标签并将其插入到新表中 tag_id | tag_nm 只使用 MySQL？

Answer 1

这是我使用 PHP 的尝试...，我想这可以通过巧妙的 MySQL 查询来提高效率。我也把它的关系部分放在那里。没有转义和错误检查。

$rs = mysql_query('SELECT `venue_id`, `tag` FROM `venue` AS a');
while ($row = mysql_fetch_array($rs)) {
    $tag_array = explode('|',$row['tag']);
    $venueid = $row['venue_id'];
    foreach ($tag_array as $tag) {
        $rs2 = mysql_query("SELECT `tag_id` FROM `tag` WHERE tag_nm = '$tag'");
        $tagid = 0;
        while ($row2 = mysql_fetch_array($rs2)) $tagid = $row2['tag_id'];
        if (!$tagid) {
            mysql_execute("INSERT INTO `tag` (`tag_nm`) VALUES ('$tag')");
            $tagid = mysql_insert_id;
        }
        mysql_execute("INSERT INTO `venue_tag_rel` (`venue_id`, `tag_id`) VALUES ($venueid, $tagid)");
    }
}